Vitamin, Gene, and Enzyme Replacement Therapy

How is vitamin, gene, and enzyme replacement therapy useful in the identification, treatment, and prevention of birth defects?

Vitamin therapy. There is a wealth of research occurring in the area of nutrition and how it plays a role in either causing, preventing, or decreasing the chances for disease. Similarly, there has been research into the nutritional causes of birth defects. One such discovery involves a B vitamin called folic acid. Taking folic acid one month before and during the first trimester of pregnancy has been shown to reduce the risk for many birth defects including open neural tube defects (such as spina bifida), heart defects, and others. For this reason, the Centers for Disease Control and Prevention recommends that all women who might become pregnant should take a daily multivitamin containing 400 micrograms of folic acid.

Gene therapy. Gene therapy is a term used to describe "inserting" or somehow "giving" a person the normal gene that they are missing, or replacing a gene that is defective in some way. One disease where gene therapy has been utilized is known as SCID. Severe combined immunodeficiency diseases (SCID) is a group of very rare, life-threatening diseases that a child is born with. The diseases cause the child to have very little or no immune system. As a result, the child's body is unable to fight off infections that are everywhere. This disease process is also known as the "boy in the bubble" because living in the normal environment can prove fatal to these children. Approximately one in 50,000 to 100,000 children are born with this inherited disease.

Simply put, gene therapy for SCID involves taking the patients' own blood and putting the normal gene into the blood cells. The patient is then given a blood transfusion with their own blood that has the normal gene inserted, which then integrates into the immune system, which lessens the symptoms of the disorder. The process is very complicated and not successful in every patient. There is a great deal of research into this promising area of medicine with the hope that other diseases can be treated in this manner.

Enzyme replacement therapy. Genes code for proteins, and proteins are essentially enzymes. So, when a gene is mutated and does not produce the gene product, an enzyme is missing or defective. One way to treat a genetic condition is to replace the enzyme that the gene is not producing. Gaucher disease is one of several conditions for which enzyme replacement therapy has been developed.

Patients with Gaucher disease have abnormal accumulations of a compound called glucocerebroside due to the deficiency of the enzyme glucocerebrosidase. This accumulation causes cells to form what is known as "Gaucher cells" which displace healthy cells in bone marrow, cause an enlargement of the liver and spleen, organ dysfunction, and deterioration of the skeleton. There are three different types of Gaucher disease which range in terms of severity and age of onset. An enzyme assay can confirm the diagnosis.

Enzyme replacement therapy (ERT) has been used in the treatment of Gaucher disease to reverse the symptoms and improve the quality of life. It must be taken throughout the life of the individual, otherwise the health problems from the gene defect return. Patients must be under the care of a doctor to monitor the therapy for any adverse reactions and adjust dosages.